The present invention relates to vehicle sensing systems. More particularly, the present invention relates to a method and system for performing object detection utilizing a single vision sensor.
Various sensing systems currently exist for performing collision warning and countermeasure system operations, such as detection, classification, tracking, and relative distance and velocity estimation of objects within a close proximity of a host vehicle. Sensing systems also exist for performing other sensing system operations, such as occupant related operations and adaptive cruise control operations.
Collision warning and countermeasure system operations include providing a vehicle operator knowledge and awareness of vehicles and objects that are within a close proximity of the host vehicle to prevent colliding with those objects. Countermeasure systems exist in various passive and active forms. Some countermeasure systems are used to aid in the prevention of a collision, others are used to aid in the prevention of injury to a vehicle operator.
Certain collision warning and countermeasure systems are able to sense an object within a close proximity of the host vehicle and warn the host vehicle operator such that the operator can take precautionary steps to prevent a collision or injury. Other collision warning and countermeasure systems activate passive or active countermeasures such as airbags, load limiting seatbelts, or brake control whereby the system itself aids in the prevention of a collision or an injury.
Occupant related operations include the detection of occupant characteristics, the determination of which safety system countermeasures to perform, and the adjustment of deployment or enablement times and rates of the countermeasures. Example countermeasures that may be enabled are seat belt pretensioners and airbags. Occupant characteristics may include occupant positioning within a seat, occupant size, or other known occupant characteristics.
Adaptive cruise control operations include adjusting a host vehicle traveling speed to maintain a safe operating distance between the host vehicle and a target vehicle. Other similar sensing systems also exist, such as lane departure and lane-keeping systems, which monitor lane markers or roadway lane designating lines and provide warnings when the host vehicle is not maintaining travel within a current operating lane.
The various sensing systems may be ultrasonic, radar, lidar, or vision-based. In order to perform each of the various sensing system tasks many of the stated sensors are distributed throughout the host vehicle. Not only does each of the sensors increase vehicle manufacturing and maintenance costs, but in order to perform object detection and assessment multiple sensors are needed.
Also, various techniques have been utilized, such as triangulation, in determining range, velocity, acceleration, and identification of objects in relation to a host vehicle. Typically, two or more cameras are used to determine the stated parameters, potentially further increasing the number of sensors used.
One technique, that is used to reduce the number of sensors within a host vehicle, uses vision sensors and performs optical flow visual image processing to estimate range of a target. In essence the technique infers three-dimensional characteristics from two-dimensional information. Other image processing techniques assume target size, based on a known range of vehicle sizes, and estimate range, based on the assumed size or an apparent two-dimensional size and image pixel intensity. The stated techniques tend to be inaccurate due to the assumptions and estimations contained therein.
Thus, there exists a need for an improved sensing system that decreases the number of sensors to perform object detection and determines object parameters associated with the detected objects. Reduction in the number of sensors can aid in reducing the number of related vehicle components, system complexity, and vehicle manufacturing and maintenance costs.